Magnetic materials characterization using a fiber optic magnetometer

The fiber optic magnetometer is a relatively new sensor concept which shows promise for high sensitivity measurements. It employs glass fibers which are configured in a Mach–Zehnder interferometer where the fringe pattern output is extremely sensitive to path length changes. The sensing leg is sensitized to magnetic fields by electroplating the fiber with magnetostrictive Ni-Fe-Co alloys. The magnetic M properties of the metal-coated fiber are measured using an M-H looper and its magnetostriction λ using the fiber magnetometer setup. Data for Ni-Fe alloys are presented which compare the measurements of M and λ versus tension. From this data physical relationships between λ and M for the metal-coated fibers are identified.